Geothermal drilling projects, especially large ones involving hundreds to thousands of holes, require meticulous planning and oversight to avoid costly mistakes and ensure environmental compliance. However, this is easier said than done, as it can be challenging to spot the signs of failure before it is too late when engulfed in the work yourself. 

Fortunately, by recognizing what red flags on geothermal sites look like and which red flags pose the most threat to your success, you can avoid the negative outcomes of pushing on despite the warning signs without fail. The biggest red flags to look for on a geothermal project include inadequate testing, uncertain disposal plans, and potential environmental issues. Although knowing what they are can certainly help in identifying them moving forward, let’s dive even deeper below into what each red flag means, how it can be handled, and what a lack of forethought can lead to. 

Key Red Flags in Geothermal Drilling Projects

Although red flags in geothermal drilling can vary wildly depending on the job site, the team, and even the rig, below are the most common red flags every geothermal drilling professional should be aware of for success. 

1. Incomplete Testing

Before commencing any large-scale geothermal project, it is critical to have complete and thorough testing data. This includes evaluating test well logs and in-situ thermal conductivity tests. These tests provide vital information about the geothermal properties of the site and help predict the project’s feasibility and success. If a project pushes forward without complete testing data, it poses a significant risk of encountering unforeseen challenges that can escalate costs and complicate project execution.

2. Lack of Historical Geological Data

Understanding the geological history of the project area is crucial. Drillers should access all available geological logs from previous drillings within the same area, including those available from geological surveys like the USGS or relevant local entities. This historical data can offer insights into potential drilling difficulties or environmental concerns that might not be evident from surface studies alone.

3. Environmental and Disposal Concerns

One often overlooked aspect of geothermal drilling is the disposal of drilling spoils. The volume of material removed from each borehole can be substantial. For example, a 400-foot hole with a six-inch diameter yields approximately 3.5 cubic yards of material. Proper disposal of these materials must be planned and priced into the project, as failing to do so can lead to significant environmental and regulatory issues. Environmental regulations may dictate specific disposal methods, and the costs associated with these processes can be substantial.

4. Potential Artesian Flow and Contamination

When drilling to significant depths, there is a risk of encountering artesian flows or contaminating groundwater sources. These scenarios can lead to additional regulatory scrutiny and may necessitate mitigation strategies that can increase project costs and complexity. Properly assessing these risks through preliminary tests and historical data is essential.

5. Underestimating the Cost of Disposal

The logistics and cost of disposing of drilling spoils must not be underestimated. The cost of back truck services, necessary for transporting spoils, can be a significant part of the project's budget, especially if environmental regulations require special handling. Ensuring that the project budget adequately covers these costs is crucial for avoiding unexpected financial burdens.

Don’t Ignore the Signs

Being aware of these red flags is crucial for geothermal drillers and company owners to plan and execute successful drilling projects. Proper testing, thorough historical data review, environmental compliance, and realistic budgeting for disposal and potential complications are vital factors that, if ignored, can turn a promising geothermal project into a problematic endeavor. Proactively addressing these issues will lead to more predictable outcomes and sustainable project success.

To hear more about this subject from industry leaders, take a look at this edition of the ‘Ask Brock’ series, ‘What Red Flags to Look for on a Big Geothermal Project.’